Vulcanization of rubber



wise activate my new accelerators.

PatentedJan. 11, 1944 UNITED STATES 1 2,338,863 PATENT OFFICE VULGANIZATION or RUBBER Roger A. Mathes, Akron, Ohio, assignor to The B. F. Goodrich Company, New York, N. Y., a corporation of New York Serial No. 371,579

No Drawing. Application December 24, 1940,

Claims.

ed in a variety of-ways, and include such compounds as 2-mercaptothiazoline, Z-mercapto 4- methyl thiazoline, 2-mercapto' 4,5-dirnethyl thiazoline, 2-mercapto 4-ethyl thiazoline, 2-mercapto 4,5-diethyl thiazoline, Z-mercapto 4-phenyl thiazoline, 2-mercapto 4-methoxy' thiazoline, 2-mercapto 4,5 tetramethylene thiazoline, 2- mercapto 4-p-aminophenyl thiazoline, and the like. For the other component oimy new class of accelerators, any halogenated acyl derivatives of any aryl amine may be used, such as alphachloroacetanilide, alpha-chloroacetoacetanilide, alpha-chloropropionanilide, alphachloro p-nitracetanilide, alpha-chloro o-bromacetanilide, alph'a-dichloroacetanilide, alpha-dichloro propionanilide, alpha chloracettoluidide, alpha chloroacetoacettoluidide, alpha-dichloroacetto1 uidide, alpha-chloroacetxylidide, and the like.

Monocarboxylic acids, saturated or unsaturated, and their metallic salts, which serve as activators for z-mercaptothiazoline, as disclosed in the copending application of Jones and Mathes, Serial No. 255,358, filed February 8, 1939, like- Acids which may be used comprise stearic, lauric, caprylic, linoleic, oleic, palmitic, benzoic, salicylic, and the like; the salts of these acids with sodium, potasmagnesium, lead, zinc, tin, and any other alkali, alkaline earth, or heavy metals may also be used. An appreciable activating effect-is obtainable with only a trace of these materials, but it is preferred to use from 1% to 5% or more.

My accelerators may be made by reacting equimolecular proportions of the thiazoline and the monochloro-acyl amine, or by reacting two moles of the thiazoline with the dichloroacyl amine. In the preferred form of my invention the reaction is carried out by boiling the thiazoline and the chloroacyl amine with an alcoholic alkali solution for a short time, then filtering oi! the sodium chloride produced and evaporating the solvent.

As a specific example of my invention I have prepared an accelerator by refluxing for about half an hour a mixture consisting of 6.8 g. of alpha-chloroacetoacetanilide, 3.8 g. of 2-mercaptothiazoline, and 1.4 g. of sodium hydroxide in 50 ml. of ethyl alcohol. At the end of this period the reaction mixture was cooled, filtered, and the solvent was removed by evaporation to leave an oily product.

5. This reaction is believed to proceed as follows:

I have also preparedan accelerator by refluxing a-mlxture of 3.3 g. c1 2-mercaptothiazoline, 5 g. of alpha-chloroacetanilide, and 1.2 g. or sodium hydroxide in 50 ml. of ethyl alcohol for about one-half hour, cooling, filtering, and GVflP-v orating the alcohol to, leave an oily product.

The product of this reaction is believed to be formed as follows:

When compounded with rubberin the following recipes and cured in a mold at 287 F. my accelerators gave stocks with the following physical properties, where T is ultimate tensile strength in pounds per. square inch, and E is elongation at break in per cent:

v. A 1 B Timaofcure;minute's T E '1" E m 2,530 sou 2,400 ass 30 8,085 800 3,070 825 3,42) 780 8,270

These results clearlyshow thatmy new accelerators provide a vulcanized rubber composition -60 having valuable properties.

Our new accelerators are efiective not only with natural rubber or caoutchouc, but also with balata, gutta percha, latex, rubber isomers, or any senthetic rubber which can be vulcanized, that is, which loses its property of thermoplasi-icity and becomes elastic when heated in the presence of sulfur, and the term "a rubber is used, in the claims to designate all of the above mentioned materials.

Pigments, fillers, reinforcing agents, antioxidents, softeners, other accelerators, etc., may also be present in the composition.

Compositions made with my accelerator may be put to a variety of uses, such as for pneumatic and solid tires, belting, hose, foot-wear, surgical goods, latex dipped goods, all manner molded goods, and the like.

For the vulcanizing of compositions containing my accelerator any of the usual methods may be used, such as heating in a mold, in

steam, hot air, hot water, etc.

Although specific embodiments oi. my inventlon have herein been disclosed, I do not intend to limit myself solely thereto, for many variations and modifications lie within the spirit and scope of my invention as defined in the appended claims.

I claim:

1. The process of vulcanizing a rubber in the presence-of an N-acylated aryl amine of the structure a in which there is attached to the carbon atom adjacent to the carbonyl group at least one and not more than two groups of the structure structure in which there is attached to the carbon atom adjacent to the carbonyl group one group or the structure 11 NCEa -s-c S- -Ra Ra in which R1, R2, R3, and R4 are members of the class consisting of hydrogen, hydrocarbon, and alkyl ether groups, the remaining free valences of said carbon atom being satisfied by members of the class consisting of hydrogen, hydrocarbon, and acyl groups, and in the presence of a member of the class consisting of monocarboxylic acids and their. metallic salts.

3. The process of vulcanizing a rubber in the presence of an N-acylated aryl amine of the structure in which there are attached to the carbon atom adjacent to the carbonyl roup two groups of the structure in which R1, R2, R3, and R4 are members 01' the boxylic acids and their metallic salts.

4. The, process of vulcanizing a rubber in the presence of a compound with'the structure N-cm and of a member of the class consisting of monocarboxylic acids and their metallic salts.

5. The process or vulcanizing a rubber in the presence of a compound with the structure and of a member of the class consisting of monocarboxylic acids and their metallic salts.

6. A composition comprising a rubber vulcanized in the presence or an N-acylated aryl amine of the structure in which R1, Ra, R3, and R4 are members oi. the a class consisting or hydrogen, hydrocarbon, and

alkyl ether groups, the remaining free valences of said carbonatom being satisfied by members of the class consisting of hydrogen, hydro-v carbon, and acyl groups; and in the presence of the structure a member of the class consisting of monocarboxylicracids and their metallic salts.

'7. A composition comprising a rubber vulcanized in the presence of an N acylated. aryl amine of the structure in which there attached to the 'atom' adjacent to the carbonyl group one group of in which R1, Rs. I ls, and R4 are members of the class consisting of hydrogen, hydrocarbon, and alkyl ether groups, the remaining free valences of said carbon atom being satisfied by members 01' the class consisting 01' hydrogen, hydrocarbon, and acyl groups; and in the presence of a member of the class consisting of monocarboxylic acids and their metallic salts.

8. A composition comprising a rubber vulcanized in the presence or an N-acylated aryl amine oi the structure i ikmpo-a in which: there are attached to the carbonjatom adjacent to the carbonyl group two groups or the structure r v i N-o or the class consisting of hydrogen,"hydrocar- ,bon, and. acyl groups: and in the presence'oi a member of the class consisting-oi. monocarboxylic acids and their metallic salts. I

9. A composition comprising a rubber :vu1-

canized in the presence oi'a compound the-structure H.011]

with

and a member of the class consisting oi monocarboxylic acids and their metallic salts.

10. A- composition comprising a rubber ,vul-

canized in the presence of a compound with the structure and a member 01 theclass consisting of monocarboxylic acids and their metallic salts.

' ROGER A. 

